Mohamed Shawki's goal in the dying seconds of the first period broke the deadlock before Mohamed Abou-Treika doubled the lead seven minutes after the interval.
Mohamed Adel chipped over injured keeper Essam Al-Hadari one minute later to narrow the gap but Emad Meteb converted home later on to end the visitors' hopes.
Al-Hadari's attempt to palm away a lofted pass in the 12th minute left him moving uncomfortably through out the game.
Although Ahli had substitutions, Al-Hadari remained on the pitch.
Abou-Treika could have widened the gap from the spot midway through the second period but he slammed the ball over the crossbar.
The victory pushed Ahli up to second place, one point behind Ismaili with two matches in hand while Suez were left 10th with 15 points.
Egyptian international midfielder Shawki opened the score line in the 45th minute when he threaded the ball past advancing goalkeeper Ali Hegazi after a flick-on from Angolan striker Flavio.
Ahli went two up in the 52nd minute when Hegazi couldn't block Abou-Treika's shot on the rebound after he parried Hossam Ashour's low shot into his path.
Adel pulled one back shortly after as he capitalized on Al-Hadari's slow movement to loft the ball over his head after being found unmarked inside the box.
African Footballer of the Year nominee Abou-Treika couldn't take his season tally to six goals later, firing wide from the spot in the 70th minute after Meteb was allegedly pulled inside the area.
The television replay proved that the international forward simulated to win the penalty-kick.
But Meteb opted to stand on his feet six minutes later to convert Osama Hosni's cross into the back of the net.